An X-ray computed tomography device (hereinafter, referred to as CT (Computed Tomography)) and other modalities thereof are used to collect three-dimensional data.
For example, a three-dimensional image in which view point is placed inside a tract of a tubular body such as the digestive tract, trachea, blood vessels, etc. may be made based on the three-dimensional data (volume data) collected from CT. Furthermore, references made to the three-dimensional image may include the three-dimensional data.
A large intestine analysis system exists for carrying out preoperative diagnosis including a screening test. For example, large intestine analysis by CT (CTC: CT colonography) is known.
In CTC, as an example, a displaying method using virtual endoscopy (VE) is used, the endoscopic observation due to virtual endoscopy (VE) being able to carry out based on the view point location placed inside the tract of the tubular body. Furthermore, the images displayed upon virtual endoscopy may be referred to as virtual endoscopic images.
Generally, upon endoscopy for intratubularly observing the large intestine, there is an unobservable region towards the interior of the tract, in which a crescent-shaped crease becomes a blind spot. This is because the view point location cannot be optionally set with endoscopy.
In contrast, with virtual endoscopy (VE), the view point location may be optionally set. In virtual endoscopy, regions that become dead spots and cannot be observed depending on the view point location (non-observation region) are generated; however, these may be become to observable regions by shifting the view point location.
Moreover, with CTC, a displaying method by multi-planar reconstruction (MPR) is used, the multi-planar reconstruction allowing extracting and displaying of an optional cross-section using the three-dimensional image. Furthermore, the image displayed by multi-planar reconstruction may be referred to as an MPR image.
In multi-planar reconstruction, the view point location upon virtual endoscopy and the presence of a lesion candidate may be comprehended by displaying the view point location upon virtual endoscopy on the MPR image.